A mass balancing mechanism of the above-noted type is known from the German periodical “Motortechnische Zeitschrift MTZ”, Issue 10/2006, and mostly serves as a so-called Lancaster compensation to compensate both the free mass forces of the second order and the free mass moments of inertia of the second order about the longitudinal axis of the internal combustion engine in a four-cylinder, in-line internal combustion engine. In the cited periodical, the compensation shafts driven by a chain drive extend for this purpose on both sides of and at different heights relative to the driving crankshaft of the internal combustion engine. Inversion of the direction of rotation of one of the compensation shafts is achieved through a spur gearing comprising two helical spur gears arranged between one of the shaft-side chain sprockets and the associated compensation shaft.